A plurality of cable holders have been developed which facilitate the mounting and retaining of conductors. Many of these holders are permanently mounted. Removal thereof often destroys the holder and mars the surface to which it was mounted. These holders often require tools and other parts such as fasteners or clips. Installation and removal of these holders is time consuming and typically requires an installer to use two hands.
Advances in the development of plastics and adhesives provided alternatives to the use of tools and a multiplicity of parts. U.S. Pat. No. 2,701,819 (S. A. Hirtle) describes an electrical cord having a surface coated with an adhesive to enable the cord to be easily attached to a wall. A thin strip of insulating material could also connect a pair of metallic conductors, and then the adhesive would be applied to the underside of the flat insulating strip. A longitudinally scored centerline and a plurality of spaced holes provides means for separation when the cords are to be used singly. Mounting of this cord is typically a two-handed operation to ensure that the cord is straight, flush, and mounted in an attractive manner. One drawback is that the cord is still exposed to view after attachment.
U.S. Pat. 2,704,302 (R. W. Budd) describes apparatus comprising a plano-convex base, a projection extending from the side of the base, a longitudinal bore extending through the center of the projection, and a longitudinal slit extending down the upper surface of the projection. An adhesive material is applied to the plano side of the base. The apparatus has a considerable cross section compared to the cavity which holds the conductor. This ratio of cross section to cavity area adds to the cost of material and weight of the apparatus. Repeated flexure of the joint area between the plano-convex base and the projection could also cause fatigue and cracking of the material.
Belgian Patent No. 571,724 (J. L. C. Wuyts, et al.) describes an apparatus with a cross section resembling a slightly closed letter U. The cavity area is shaped to complement the shape of the conductor to be inserted. A large portion of the upper surface of an inserted conductor remains exposed. This is particularly unsightly if the conductor shape and color did not match the apparatus.
The apparatus described in U.S. Pat. No. 2,885,460 (J. Borresen and G. N. Pettersen) has a cross section which is similar to the apparatus of the above-described Belgian Patent. Again, a large part of the captive conductor is exposed from the uncovered groove of the retaining apparatus. This diminishes retention capability and can be unsightly.
The Adhesively Secured Electrical Devices described in U.S. Pat. No. 3,029,303 (J. Severino) have a cross section with a flat, adhesively backed base, and sidewalls which approach the apex of a triangle but then hook downward to form a V-shaped upper surface with a slot at the bottom of the V. This V-shaped upper surface allegedly aids during insertion of a conductor, but the hook-shaped inner surface of the sidewalls impedes removal of a conductor placed therein and strains the adhesive bond to the mounting surface.
Mitchell et al. "Cable Enclosure" (IBM Technical Disclosure Bulletin, Vol. 12, No. 12, May 1970, Page 2293) shows another apparatus with a V-shaped upper surface. Cables can be inserted or withdrawn by spreading the flexible closure with an appropriate tool. As in the device of Severino described above, the V-shaped upper surface impedes removal of a conductor.
S. Pinnolis' "Wire Securing Clip" (Western Electric Technical Digest, No. 50, April, 1978, pages 23 and 24) shows lateral portions of a wiring clip which has thickened rounded edges formed thereon. These edges are biased toward each other by residual stress from a molding operation. In another embodiment, U-shaped clasp sections are formed on the end of each lateral section, which clasp sections engage each other after insertion of each individual wire. This hooking action impedes the easy, one-handed insertion and removal of conductors.
The Ducting System for Wiring Having Channel Alignment Interface Members described in U.S. Pat. No. 4,602,124 (D. Santucci) shows a generally U-shaped channel comprising a bottom and a pair of spaced sidewalls. Parallel slots on the inner surfaces of the sidewalls permit flat cable retainers to be snapped into these slots. A U-shaped channel slips over the channel and flat cable retainer assembly. A multiplicity of different parts needs to be stocked to practice this invention.
German Printed Application No. 2,232,945 (G. Flegler) shows a cable duct composed of two different channel-shaped sections, one fitting over the other. Fine teeth on parallel sections of both sections engage each other to hold the lid section securely in place. Different parts must be stocked to practice this invention.
United Kingdom Patent Specification No. 1,206,101 (J. Walton) shows an electrical conduit in several configurations to provide a hollow formation with a longitudinal narrow opening. In some applications the conduit is placed in walls or floors in open channel ducts. A tool is needed to draw cables into the conduit and another tool is needed to install wires in the conduit at corners and other recesses.
U.S. Pat. No. 4,255,610 (M. A. Textoris) shows a wiring system for an office partition assembly in which mitered panel channels engage mitered post channels. An integral hanger assembly is removably attachable to the partition assembly adjacent to each post which separates and supports each partition. The hanger assembly includes hook means which engage slotted members to retain the hanger assembly. A single hanger assembly at each post face serves not only to support panel wiring channels, but also a similarly configured post wiring channel. The practice of this invention requires very specific hardware, the hanger assembly, and very specific slotted members to receive and support the hanger assembly. In addition to the increased cost of this hardware, the invention cannot be practiced in installations which do not provide suitably slotted members for support.
French Patent No. 1,409,853 (R. Soranzo) shows a cross section of apparatus having two or three cavities. An upper surface is slotted to permit insertion of a conductor. The upper surface must be raised to insert the conductor because of the webs which separate the interior of the cavity. Prying up the top surface requires the insertion of a sharp tool or is at least a two-handed operation.
German Printed Application No. 25 40 840 (E. Cramer) shows apparatus having a plate-shaped cross section which contains circular grooves which are connected to a top surface by an aperture. There is a large ratio of material cross section to the useful cavity cross section which adds cost and weight to the apparatus. The heavy cross section of the members which needs to be deformed for insertion of the conductors also impedes a quick, easy, and single-handed operation which is desired.
The 3M Company produces a product with the trademark "Scotchflex" for a cable duct which has a flat adhesive backed base, and an upper section which is approximately oval shaped, where one side hooks into a groove in the upper section. This hooking action impedes the easy, one-handed insertion and removal of conductors.
It is desirable to have apparatus which houses electrical or optical conductors, or intravenous fluid conductors in hospitals or ambulances, is relatively inexpensive to manufacture, is of good appearance, facilitates ease of insertion and removal, has a relatively long lifetime, and is able to retain conductors in the presence of inadvertent pulling of the conductors.